The present invention relates to a method and apparatus for effecting the automatic insertion into predetermined apertures in a printed circuit board the lead wires of electric and electronic parts such as resistors and diodes, the lead wires being extended in opposite directions coaxially of a main body of a part.
In general, the prior art part insertion methods and apparatus may be divided into two types. According to one type, various types of parts are previously arrayed on a tape or belt in a predetermined insertion sequence, and such a tape or belt is directly fed to a lead wire insertion head so that the leads of the parts may be sequentially inserted into predetermined apertures in a printed circuit board according to a predetermined electric device arrangement pattern. Since the parts are attached to the tape or belt in a predetermined insertion sequence, when a failure in insertion of the lead wires of one part occurs, the insertion cycle of this part cannot be repeated.
According to the other type, there are prepared a plurality of part tapes or belts each holding a large number of parts of the same type. The desired tape or belt is selected, and a part is separated therefrom and transferred on a belt or through a pipe to an insertion head which effects the insertion of the lead wires of the part into predetermined apertures in a printed circuit board. Since the parts separated from the part tapes or belts are transferred through a pipe or on a conveyor belt, they are rotated or inclined so that the stable transfer to the insertion head cannot be ensured. Furthermore the transfer takes a long time so that the insertion cycle time cannot be shortened. Moreover the parts are damaged and the lead wires are deformed during the transfer.
In order to improve the above second-mentioned type of insertion apparatus, we have previously invented an arrangement for inserting electric parts into the apertures of a printed circuit board by grasping the parts with a chuck one by one (see U.S. Pat. No. 4,051,593). The problem of the second type of insertion apparatus was solved by this arrangement, but this construction is complicated, because the cut electrical part is horizontally rotated and transmitted and rectangularly and vertically rotated by the chuck.